Differential-gear control mechanism



@Wma l. C. WOODWARD DIFFERENTIAL GEAR CONTROL MECHANISM Filed Feb. 21.1923 Aug. i4, i923.

f Patented ug. i4, i 1923.-.

IRVIVNG C. WOOIDWARD, OF SYRACUSE, NEW YORK.

DIFFERENTAL-GEAR CONTROL MECHAISM.

v.M iplication led February 21, 1923. Serial No. 620,336.v

To all whom t may concern.'

Be it'known that I, lnviNG. C. Woonwann, a citizen ofthe United Statesof America, and a resident of Syracuse, county of Onondaga, 'and Stateof yNew York, have invented a new and useful Improvement inDifferential-Gear Control Mechanisms, of which the following is aspecification.

This invention relates to differential gear control mechanisms of thetype described in applicants Patent No. 1,855,297, October 12, 1920.

The objects of the invention are to provide improvements in the clutchoperating mechanism whereby this mechanism is simplied, made morecompact and improved in its operation.

The device herein described in principle is similar to the patentedconstruction above referred to. Both designs are based upon the factthat differential action in vehicle drive mechanisms, in so far asactually required, is a comparativelyslow motion and of slight extent,and, therefore differential gears are improved bybeing made controllableto prevent undue motion therein, Most uncontrolled differential gearsoperate satisfactorily, except for a tendency thereof, when roadconditions permit, to produce a difference in motion between the twodriven, axles when not required or far in excess of that which isrequired. Differential gears when operatingproperly, should compensateonly for irregularities in Y road surfaces, and the difference betweenthe e curves passed through by the two driven wheels when theV vehicleis following a curved path'or making a turn. The normal maximumdifference in rate of rotation required of the two driven shafts is onshort turns. If` the vehicle is traveling in a curve of large radius,the difference of motion between the two driven axles is the same as oncurves of short radius, but is Aextended over Va greater time and lengthof travel of the vehicle. The differential `action which is necessaryfor the proper operation of the, driving mechanism is extremely slightffEven for a full 60o turn ofany radius, one wheel should rotate morejor.

4lessthan Vthe, other only the length of a circle, the radius of whichis the distance between thel drive wheels. ferential motion such .asoccurs when the brakes are applied and one engages slightly But excessdif-V in advanceof the other, is extremely dangerous, resulting in aturning torquev and possible side slipping of the vehicle.

To correct the action of standard differential mechanisms, applicant hasprovided a restraining device for the differential, which may be causedto check differ'- ential `action and thus eliminate harmful motion bymore or less compelling the two driven axles to rotate together, butalways permitting the proper slight differential rotation of the shaftsbeforeany part of the mechanism becomes strained or liable to breakunder the effort to transmit the driving torque through the axle of theinside wheel or the wheel having best traction. Likewise, this deviceprotects the axles from the excessive strain resulting from a wheelsuddenly obtaining good traction after idly speeding with little or notraction, since it never permits the racing of a' wheel.

The desired result is obtained by modifying the standard bevel geardifferential mechanism only to the exteiit'of providing clutch teeth onone of the hubs of the pinion-supporting housing and slidably mountingon the splined end of `one Aof the axles an automatically releasablecoacting clutch member and a manually controlled means for engagingthiscoacting clutch member with the clutch member formed on one of the-hubsof the differential housing. rhe clutch members have inclined teeth andare held in engagement by a spring. clination of the teeth and thestrength of the spring is arranged so that with any given rear axleconstruction the clutch members will 4 be momentarily cainmed out ofengagement with each other, due to the inclination of their teeth, whenthe stresses produced by effort tol dierentiate between the axles reacha predetermined amount.

improved means are provided for engaging and disengaging the clutch andfor retaining the movable member of the clutch in either of its setpositions.

The purposes of the invention may beaccomplished by a construction suchas shown in the vaccompanying drawing, wherein z- Figure l isafragmentary plan view in section, of the rear axle partof a. vehicledrive mechanism equipped with the present improvements.

Figure 2 is a sectional detail taken on the line 2 2 of Figure l.

The ini Figure 3 is a detail view of one of Vthe locking pins forretaining the movable member of a clutch in disengaging position.

Figure i is anV enlarged sectional detail illustrating how Vthe clutchis retained in disengaged position.

The drawing illustrates a Vstandard'construction ot well-known design,except 'lior v casing t oi the diii'erential enffaeement with the teeth2O C t:

the few additions required by the present improvements. The well-knownparts oi" the construction constitute a rear axle housing l enclosingthe weil-known diitlerential gearing- 2, and ring gear 3 supported bythe gearing and meshing with pinion 5 secured to the propeller shaft (i.T he differential 'fear casing d is made in two parts, 7 and 8, clampedtogether by the cap screws l), and each having an extended hub l0 andil, respectively, surrounding which are the bearings l2 and i3. Theaxles 14 and l5 are splined in the customary way to the beveled gears.i6 and 1T of the differential gearing and which mesh with theintermedate pinions 19.

For the purposes ot the present improvements, the hub il oll the part 8of the dilerential gear casing extends slightly beyond bearing 13 and atthis end is provided with inclined teeth for coacting with similarlyinclined teeth 2l on a sleeve 22 splined to engage the extended splineson axle l5. A helical spring 2d normally urges the teeth 2l on theclutch element or sleeve 22 into on hub il ot the differential gearcasing'. 'lhe sleeve 22 is drilled radially to receive a plurality ofpins in positions to rest upon the tops of splines 2B. These pins arepreferably centrally grooved to receive retaining springs or clips 26which serve to rictionally retain the pins 1n the holes in the sleevebefore and during the assembly oi' the mechanism. The clutch member 22and the spring 24C which bears between the clutch member and awasher 26fitting the splined partoit axle l5, are surrounded by a sleeve 2'?,which has an annular and inclined 'internal Vshoulder 28 forl engagementwith the pins 25. Thus, it sleeve 27 is shifted to the right, Figure l,it will engage the pins and the clutch member 22 and move the clutch todisengaged position. When the teeth ,21 are disengaged from the teeth20, the pins 25 are cammed downwardly by the shoulders 28V into recesses29 cut in the; surfaces of splines 23. The sleeve 27 in its continuedmotion, moves relatively' to the pins 25, the reduced diameter 30 ot thesleeve engaging the outer surfaces of the pins. The clutch is by thismeans locked in its disengaged position, Figure 4:, as due to thereduced Vdiameter 30 ot the sleeve 27, the pins cannot ride upovershoulders Slat the inner endsof recesses 29.

For the purpose of shifting sleeve 27 to secured to the axle easinfrtube 36. This tube has a small opening 3i through which the gearextends. The shaft 34 is provided with an arm 38 to which are attachedsmall twisted wire lines 89, leading over pulleys to thedashboard oi thevehicle in convenient location lor Aoperation by the driver;

ln the operation of the device, assuming that clutch 22 is in theposition indicated in liigure 1i, the axles lei and i5 willrotate at thesaine rate due to the clutch connection beween axles i5 and thecasinglof the ditierential gearing. The clutch element 22 niust alwaysrotate with axle l5, because ot' the splined connection therewith, asYindicated in Figure 2, but due to the inclination oit' teeth 2l) and 2l,it 'therefis sutlicient eti'ort to differentiate in speed between theaxles la and l5, clutch 22 is cammed i out ol engagement with the teethon hub il, thus permitting a relative rotation between axles le and 15.The clutch 22 will, however, immediately reengage the teeth on hub llatler` a slight relative motion between the axles, and may again bedisengaged and reengagedA so long as there is sufficient diiterence inresistance between the two driven wheels to cause such act-ion of thelclutch mechanism. v The inclination ot teeth 20 and 2l and the strengthof spring `2a is arranged to permit the unclutching movementY at anydesired torsional effort between the `axles 14 and l5. ln this manner'while undue differential action is prevented, a limited difierentialmotion is permitted between theV two axles before themechanism becomesunduly strained. i j

'During .normal driving under `good road conditions tree action of thedifferential mechanism may be desired;V therefore, the clutch 22 Vmay bedisengaged and' held in its disengaged position bya partial rotation otshaft Bel. in a lett-handv direction-rFigure The gear 23 by engagementwith the annular rack teeth 32 on sleeve 27 causes this sleeve to shiftto the right and' carry with it through the pins 25, the clutch.element'22, which is Ysplined toaxle 15. After pins 25 have .been forcedinto the recesses 29 and splines 23, the shoulder 28 on sleeve 2T-passes the pins 25, and the reduced diameter 30 o'l the sleeve` thenserves te lock the pins against movement ont of the` recesses V29. TheVclutch element 22 ist inl this manner locked out of engagementwiththeteeth on be altered or omitted action of spring 24 in forcing theclutch member 22 back to reengaging position.

Although but one speciiic embodiment of this invention 'has been hereinshown and described, it Will be understood that numerous details of theconstruction shown may Without departing from the spirit of thisinvention as defined by the following claims:

, I claim: Y

l. In a mechanism of the class described,

Y a pair oi' axles, differential gearing connecting said axles, meansfor driving said dit erential gearing, a casing for said diii'erentialgearing, having inclined clutch teeth formed thereon,"a clutch memberhaving inclined teeth for coacting With the teeth on said differentialgear casing, said clutch member being Vsplined to one of said axles, aspring for urging said clutch member into engagement With the teeth onthe gear casing, means for disengaging said clutch mem ber, comprising asleeve arranged for shifting said clutch member against the action ofsaid spring and being provided With rack teeth, and a pinion forengaging said rack teeth.

2. In a mechanism of the class described,

a pair of driven axles, differential gearing connecting said axles,means for driving said diiierential gearing, a casing for saiddifferential gearing, having inclined clutch teeth formed thereon, aclutch member having inclined teeth for coacting with the teeth on saiddifferential gear casing, said clutch member being splined to one ofsaid axles, a spring for urging said clutch member into engagement withthe teeth on the gear casing, means for disengaging said clutch member,comprising a sleeve arranged for shifting said clutch member against theaction of said spring and being provided with annular rack teeth, and apinion for engaging said rack teeth.

3. A mechanism of the class described,

comprising a pair of axles connected by a diierential gearing carryinginclined clutch teeth, a coacting clutch element in the *form of asleeve splined to one of said axles, and provided with radial holesWithin which are mounted pins, a sleeve surrounding said clutch memberprovided with a shoulder for engagement with said pins for the purposeof shifting said clutch member, and recesses in said axles which areentered by said pins after the clutch is disengaged, said shoulder thenserving to lock the clutch in disengaged position by bearing on theouter surfaces oi' said pins.

4. A mechanism of the class described, comprising a pair of axlesconnected by a dierential gearing carrying inclined clutch teeth, acoacting clutch element in the form of a sleeve splined to one of saidaxles, and provided With `radial holes Within which are mounted pins, asleeve surrounding said clutch member provided With an inclined shoulderfor engagement With Said pins for the purpose of shifting said clutchmember, recesses in said axle which are entered by said pins after theclutch is disengaged, due to the camming action of said shoulder, saidshoulder then serving to lock the clutch in disengaged position bybearing on the outer surfaces of said pins, means for shifting saidsleeve, and a spring for urging the clutch into engagement.

Signed at Syracuse, New York, this 16th day of Feb., 1923. y

IRVING C. WOODWARD.

